How the Eye Sees Color

What is color and where does it come from? Do all creatures see the same colors and shades? The world of color affects not only what we see, but even emotions. To understand how the eye sees color, an examination of its source can be helpful.

Sir Isaac Newton discovered in the 1600s, that sunlight has no color and appears to be white. But this “white” light actually contains the seven colors of the rainbow: red, yellow, orange, blue, green, violet, and indigo.

Colors are actually light waves. When light from the sun hits an object such as an orange, it absorbs all the colors except for orange. Likewise, if light hits grass in the summer, only green is not refracted. A white object means no color is refracted, all are absorbed. So white is really all the colors of the spectrum. When something appears black to us, it is because no color is refracted. Some claim this indicates that black is not a color, only the lack of any. Ask any artist or child with a crayon, and they will beg to differ.

The color spectrum is made up of varying frequencies and wavelengths. Each color has its own designated space within the spectrum. Some colors occupy more than one wavelength.

Our eyes have receptors called rods and cones, so-named for their respective shapes. Located at the back of the eye, rods help us see in dim light. Think about the fact that in dark or dim light, no color is seen, only black and white. The cones allow us to see colors, and there are three of them, one for each of the colors we mostly see: red, green, blue (RGB).

There are three distinct color systems: RGB, subtractive, and CMYK. The first, RGB, is most recognized in our television and computers monitors, as they were modeled after the human interface applied to them—the eyes. By using these three primary colors in different proportions, our screens and printers can produce up to 16 million different shades and hues of color. If you could use a magnifying glass up close on a television set, you would actually see millions of squares of colors, which make up the images viewed through red light photons. These images are conducted electronically.

In the world of art, pigments contain the three basic primary colors of red, blue, and yellow. These are the colors which cannot be made from other color combinations in paints, crayons, or pastels. This is the subtractive color theory.

CMYK is a sort of upside-down version of the RGB system. Each letter represents Cyan, Magenta, Yellow, and Black. It is through the use of these colors, in varying degrees, that millions of colors are acquired. Though it is nearly impossible to exactly replicate the colors in a parrot’s plumage or a rose petal, this system can come pretty close simply by varying percentages of use, thus creating the hues in different tones and intensities.

When it comes to seeing colors, the eyes of different species of animals have been examined for their ability to see colors as humans do. Mammals such as cats and dogs see two colors, though weakly. Yet primates see exactly as humans do. By observing the rods and cones in the eyes of such animals, scientists are able to equate a level of color in the vision field of these creatures.